Velocity fluid vacuum seal, method, and apparatus



Aug. 1:), 1926.

' o. MINTON' I VELOCITY FLUID VACUUM- SEAL, METHOD AND APPARATUS 0rigina1 1920 6 Sheets-Sheet 1 Q INVENTOR ATTORNEY Aug. 10 1926. 1,595,479

0. MINTON VELOCI'TY FLUID VACUUM SEAL, METHOD AND APPARATUS Original Filed 1920 6 Sheets-Sheet 2 ATTORNEY Aug. 10 1926. 1,595,479

0. MlNTON VELOCITY FL UID VACUUM SEAL, METHOD AND APPARATUS Origin a1 Filed Nov. 1920 6 Sheets-Sheet 5 l i I I 57 9i i l I El l E i 55 a 2 V TORNEY' Aug. 10 1926'. 1,595,479

O. MINTON VELOCITY FLUID VACUUM SEAL, METHOD AND APPARATUS or ginal Filed N vl 1920, s Sheets-Sheet 4 I I VENTfDR TTORNEY Aug. 10

0. MlNTON VELOCITY; FLUID VACUUM SEAL, METHOD AND APPARATUS 6 Sheets-Sheet 5 Original FiledNov. 30 1920 Aug. '10, 1926. 1,595,479

' MINTON ELOCITY FLUID VACUUM SEAL, METHOD AND APPARATUS Original Filed- NW5 1920 6 Sheets-Sheet;- 6

Patented Aug. 10,. 1926.

UNETED srarss OGDEN MINTON, OF GREENWICH, CONNECTICUT.

'vnroerrr rnn'rn VACUUM sEAL, METHOD, Arm- APPARATUS.

Application filedliTovembcr 30, 1920,. Serial No. 427,436. Renewed February 17, 192 6.

.My invention relates to the method of treating materials in a vacuum, and more.

particularly to the method of protecting the opening or openings into the vacuum chamber, through which opening or openi'ngs the material to be treated is introduced and withdrawn from the chamber My invention relates more particularly to avacuum seal maintained by the applica.

tion of velocity head, i. e. the difference in pressure between the atmosphere and vacuum being balanced by the velocity head of thesealing medium. Through this seal 1 the material to betreated in the vacuum chamber is passed in any suitable manner.

My invention furtherrelates more particularly tothe method of drying sheet material, as a continuous Web of paper either ing machine or directly from a vacuum chamber.

coming from the wet 'end of a paper ma chine, or from a sizing vat, or from a color-' mercury or an amalgam, or'air, or steam or water or similar fluid having the jehare acteristics above stated. In the case of water, if the material to'be treated should, for example, be a web of" paper to be dried I may protect the web by endless'rubber or water proof felts or other similar guards.

My invention further relates to employ ing passages having restricted areas merg ing into progressively larger areas between the atmosphere and the interior of the vac- 'uum chamber, forming in efiect Venturi nozzles, through which the fluid locity fluid seals flows.

of the ve- My invention further relates to such restricted passages in combination with n barometric seal and a pump; or restricted passage and Venturi type nozzle in combination with a pump to force theliquid of I may for example use the. seal thro'ughthe Venturi nozzle; or a combination of the two forms just described;

or a plurality .of nozzles opening into a single] Venturi type of nozzle in combinationwith a barometric seal; or any combination or these-different instrumentalities, or their equivalents.

My invention further relates to collecting the fluid of the velocity, fluid seal and again using it in the seal, or if the fluid is steam, collecting and using'it in the -dryers,i or using it to heat the building; or I may condense it or otherwise dispose or it.

My invention further. relates to certain steps and combinations of steps, also to certain elements and combinations of elements, whereby the method or processes herein described may be carried out, well as to certain details of-construction, all of whichi will be more fully hereinafter described in the specification and pointed out in the. claims. 3

l have shown in the drawings, difierent fo'rms of apparatus which may be used to carry out my improved method, but it isto be distinctly understood that my invention is not to be confined to the particular form of apparatua'shmvn by way of illustration. In the accompanying drawings the same reference-numerals refer to similar parts in the several figures. 'l'is a vertical section through a vacuum chamber equipped to dry sheet material, as'for example, aweb of paper, and

with two difi er'ent typesv of my velocity fluid Vacuum seals;

Fig. 2 is a vertical section, on an enlarged scale, of a detail of the/type of velocity'fiuid vacuum seal, shown on the left ofFig.l;'.

Fig.3 is a vertical section on an enlarged scale of a detail of'the type ofvelocit'y fluid vacuum seal shown onthe right of Fig.1-;.'

Fig. '4 is a detail vertical section of another modified form 01: my invention; Fig. 5 is a vertical, section or" still anothermodification in which a plurality ofv nozzles are employed;

- Fig. 8 is a vertical section of still another modification in which a plurality of nozzles are employed connected in series;

Fig. is a diagrammatic view of the simplest form of my invention;

8 is a vertical section on an enlarged scale, SliOuing a modification of .my invention in which the seal is arranged at an angle to the horizontal to obtain more or less static head.

T will describe the simplest form of my invention first, that shown diagrammatically in Fig. '4'.

The vacuum chamber 100 has a vacuum maintained therein in, any suitable manner by connecting the pipe 101 with any suitable exhausting apparatus. This vacuum chamber has two passages 102, 102 open to the atmosphere. Through these passages the material to be treated in the vacuum chamber is introduced and withdrawn. Of course if the passages wer left unguarded the vacuum in the vacuum chamber 100 would be broken. a

My invention broadly consists in guarding the passages to the atmosphere by velocity fluid vacuum seals, the velocity of the fluid being suiliciently high to prevent any air working past the velocity seal into the vacuum chamber.

In my invention suitable material may be introduced into and withdrawn from the vacuum chamber 100 through my velocity fluid seals 103, 103. It may be treated in any suitable manner within the vacuum chamber 100. It may be fed through the vacuum chamber continuously or not. 1

have shown by way of example the material in the form of a continuous web Twhich passes continuously through the vacuum chamber 100 and the velocity fluid vacuum seals 103, 103. This web 7 may be dried in the vacuum chamber, or coated, nnpregnated or treated-in any other suitable manner, and may be fedinto and out of the vacuum chamber in either direction as indicated by the arrows.

These passages 102, 102, have restricted areas 104:, 10%. Connected with these restricted areas are nozzles 105, 105. The area of the passages'102, 102 increases at 106, 106 adjacent the restricted areas 104, 10%."

Fluid which has no aflinity for or deleterious effect upon the web 7 or other material treated, is forced into the chamber 107, 107 and through the nozzles 105, 105 at sufiicient velocity toprcvent air passing through the restricted area 104- and getting into the vacuum chamber 100. The velocity required will depend on the vacuum maintained in the vacuum chamber and the fluid used for the seal. Preferably I empoly as near a perfeet vacuum as I can maintain; usually about 28 inches of mercury.

lVh'atever fiuid is used passes through the nozzles 105 with comparatively high velocity. As the fluid reaches the portion 106 of comparatively large area its velocity is reduced. he passage 102 with its restricted area 104, nozzles 105 and portions of greater area 100 is ilbcffCCt a 'Venturi type nozzle.

The )assall'e 102 is of course wide enou h to v v Y b permit th free passage of the widest web or other material to be passed into and out of the vacuum chamber 100.

The fluid which I employ for my velocity fluid vacuum seal may be mercury or an amalgam or similar material, steam, water, air or similar fluid. If water is used as the fluid and the material treated is a web 7 of paper to be dried, then I may protect the upper and lower surface of the web by rulr her or other waterproof endless felts.

If air is used as the-fluid of the seal it will be permitted to pass into the atmosphere. If water be used it may be collected in the chamber 108 and drawn oil by the pipe 100 to be used again or allowed to run to waste. If mercury or amalgam be used it would be collectedv in the chamber 108 and 'pass through the pipe 109 to be used again as shown, for example, in the other figuresof the drawings. 1f the fluid be steam it would pass from chamber 108 through the pipe 109 to beused as the heating medium in the steam drying cylinders or drums shown in the other figures of the drawings, or it may be used'to heat the building, or the pipe 109 may be connected to a vacuum pipe or condenser.

My invention is particularly adapted to be used in connection with drying sheet material in the form of paper, though it is to be distinctly understood that it is equally applicable to and covers drying sheetmaterial in the form of textile fabrics, as for example, drying such fabrics after they have been washed or bleached or dyed, or other wise treated by a liquid of some description.

I have shown my invention in connection with dry a web of paper in the other figures of the drawings.

In these other figures 1 is a vacuum chamber in which I mount a plurality of drying drums or cylinders 2, 3, 4, 5 and. 6. The wet web of paper 7 coming directly from the wet end of a paper machine, or from a colorapparatus, coating machine, printing machine, or directly from the roll of we.

)aper, is fed to the vacuum chamber 1 from the left of Fig. 1 in the direction indicated by the arrows. It is preferably, though not necessarily, received between the-upper trav- Thcse felts 8 and 9 withthe interposed wet web of paper 7 pass under the felt roll 10 in the felt roll chamber 1], through the seal 12 in said felt roll chamber, thence through cling felt 8 and the lower-traveling felt 9. I

use

- guide roll 18,

and 6 and under the second felt roll 19,-

.the drying drum or cylinder 2,

ing drum or cylinder 3, around'the guide rolls 15, 16 over drying drums or cylinders 5,

mounted in the second velocity fluid-seal, thence on the exterior of the machine, back to the first-felt roll 10 as shown by' the arrows.

The-lower felt 9, after passing under the felt roll .10, passes around the periphery of over the guide rolls 20, 21, around the felt dryer 22,

over the guide roll 23, drying drum or thence under the machine back to the guide roll 29 and again under the felt roll 10.

Among other objects of-my present invention is the reduction to a minimum of the amount of fluid, as for example, mercury amalgamor similar material, which 1 may employ for the velocity fluid vacuum seals of the vacuum chamber; also to reduce the level of the fluid within the vacuum chamber, and also, in some cases, to prevent the fluid getting into the vacuum chamber at all. 1 4

By my invention I reduce the height of the mercury in the vacuum chamber in contact with the drying drums or cylinders 2 and 6 and thereby make'them substantially as eilicient'as the other drying, drums or cylinders 3-, 4 and 5.

It is to be understood that when mercury or similar material, is placed Within the dependent upon the degree'of chambers 11 and 14c it.WOll1d flow through the restricted passages 13, 13 and would rise in the vacuum chamber 1 to a height vacuum maintained in said chamber; In a perfect vacuum it would rise 30 inches within-said chamber, the diifer'ence being the difference between the atmospheric pressure on; the mercury within the chamber 11 and the lack of pressure in the perfect vacuum maintained within the vacuum chamber. In my invention I approach as near a perfect vacuum as possible, usually employing a vacuum of about 28 inches of mercury. With such a vacuum in the vacuum chamber 1 there would be 28 inches of mereury in said chamber in which the drying drums or cylinders 2 and 6 would be immersed. This immersion requires a comparatively large qunatity of mercury, or other similar fluid.

By my invention I use velocity fluid seals to compensate for the difference in pressure between the atmosphere and vacuum in the chamber. In this manner I can prevent any fluid of the seals 'working into the vacuum chamber; or, I mayregulate the amount of fluid as mercury, or similar material of the seal which will flow into the vacthe rotating felt dryerl'l',

.uum chamber. This permits me .to regulate theheight of the fluid of the velocity fluidseal within the'vacuum chamber, regardless of the degree of vacuum maintained within said chamber. That is, I can so regulate the velocity ofthe fluid seal that no fluid Will-enter the vacuum chamber; or, I can so regulate the velocity that only a very small portion will enter the vacuum chamber. This insures that the periphery of the drying drums 2 and 6 will be free of the fluid of the, seal; or immersed in the fluid to a very small-extent, the degree of immersion being subject to regulatiorr. Should any of the fluid of the velocity seal find its way into the vacuum chamber it can be drawn oil by the barometric seal without substantially interfering with the drying action of the drying cylinders or drum 2.

left of said figure, I

. In Fig.1, on the have shown .one form ofv apparatus to regulate the level of the fluid of the velocity fluid seal in the vacuum chamber.

On the right of said Fig. 1,-I have shown another form of my invention, and in Figs. l, 5, 6

and 8T have shown still other modifications of my invention.

In connection with the vvelocity fluid seal shown on .the left of Fig; 1, and on an enlarged scale in Fig. 2, the fluid, as for example, mercury, or other fluid isv placed in the felt roll chamber or housing 11. Atmospherie pressure will cause themercury in the felt roll housing to reach the level 29. Itwould then' pass through the restricted area 13, into the larger area 36, and thence into the vacuum chamber 1. It would rise on the periphery of the drying drum 2 to aheight dependent upon the degree of Vacuum maintained in the vacuum chamber.

In a perfectvacuum it would rise 30 inches.

In the vacuum which rusually employ, about 28 inches, it will rise 28 inches, making the drying drum or cylinder 2 revolve in a depth of about 28 inches of mercury.

This requires an unnecessary amount ofmercury. I

In this form of my invention I employ a barometric seal 30. The pipe 31 of this seal is conncctcrlat 32 with thevacuumthe vacuum chamber 1, and. in this form 'of:

my invention, in contact with a small pora a ter;

. liquid to keep the mercury or similar material at the level 29 as indicated in Figs. 1

. and 2. Should for any reason the pump be operated at such a speed as to cause the 1ner- Till cury to backup in the felt roll housing chamber 11, the surplus fluid will pass out through the overflow 37 back to the barometric seal 30. To prevent any air getting into the vacuum chamber 1, l: locate the end 38 of the pipe 31 in the barometric seal .30. below the level of the suction pipe of the pump, so that even if the pump shouldaccidentally and momentarily operate at too great a speed. it cannot reduce. the level of the liquid in the barometric seal sutlicicnt to admit air into the vacuum chamber through the pipe 31. in this form of my invention, the parts are so located and operated that only a very smallv portion of the periphery. of the dryer 2 wi l be immersed in the mercury or similar material. as shown in In this form oi my invention Luse the restrictedpassage 13. but,

preferably, no Venturi type nozzle as in the other forms.

On the right ot Ilfl. 1, and on an en- 'HLI'QQI scale in Fig. 3, l have shown a different form of velocity fluid vacuum seal. in this form of my invention the restricted passage 13 is connected with nozzles 41, 4].

F The fluid, as for example, mercury is drawn from the felt roll housing 14 by the suction pipe 42 to the pressure pump 43, operated by the motor 44. and is forced through the pipe 45, into the nozzles 41, 41. As the mercuryor similar material passes through the restricted area 13. it is moving with considerable velocity, which velocity is reduced as the portions of increased area 46-are reached. The restricted area connected with the passage of large areas forms a Venturi type nozzle.

in this form of my invention the liquid of the seal is forcedlhroue'h the restricted area 13 of the passage with just suilicient velocity to balance the pressure of the atmosphere upon the seal,.which pressure, if not counteracted, would cause the fluid of the seal to back up within the vacuum chamber.

The drying drums or cylinders 2., 3, 4, 5 and 6 are all preferably driven at the same speed that the web is traveling and are heated by steam in any suitable manner.

The felt'dryers 17, 22 and 25'are also heated by steam or other suitable means so as to dry the felts passing over them.

in some cases I may use a combination of the velocity fluid vacuum seals shown in Figs. 2 and 3 and in Fig. l. I have shown such a construction in F g. 4, in which the felt roll chamber or housing 11 is connected with the vacuum chamber '1 by means of a passage having a restricted arealB. Connected with this restricted passage are nozzles 48, 48, through which the mercury or similar material taken from the barometric seal by means of the suction pipe 33 is forced by the pump 34- operated by the motor 35. In this form of my invention,

the mercury is forced through the nozzles 48, 48 and then through therestricted passage 13 at considerable velocity. This velocity decreases as the liquid reaches portions of greater area 49. This passage is in effeet a Venturi type nozzle. The surplus fluid then passes through the overflow pipe 37 back into the barometric seal 30. Should any of the sealing fluid Work past the nozzles 48, 48 it cannot back up inthe vacuum chamber, for it will pass through the pipe 31 into the barometric seal 80. The fluid of the seal can be withdrawn at any time by removing the plug 50. In this form of my invention the velocity of the fluid through the openings or nozzles 48, 48 and the Venturi nozzle, formed by the restricted passage 13 and progressive portions of increased area 49. will not be as high as the velocity of the fluid through the form of my invention shown in Fig. 3. In Fig. 3 the. velocity mustbe such as to equal or exceed the atmospheric pressure upon the surface of the seal, to prevent any of the fluid backing up into the vacuum chamber. In the form of my invention shown in Fig. 4 the velocity can be reduced below that shown in the other figure, for if the atmospheric pressure does cause any of the fluid to flow into the vacuum chamber it will be immediately withdrawn by means of the barometric seal.

In all forms of my invention the re stricted passage is wide enough to accommodate the widest web of paper orsheet material to be dried. The passage is made as restricted as possible to accommodate the web, and the felts should they be used, and to reduce the amount of work throw upon the pump.

I have shown another modification of my invention in Fig, 5, in which the vacuum chamber 1 is connected with the .felt roll housing 11 bv a restricted passage 51. This passage is provided with a plurality of nozzles 02. 52. 53, 53,54, 54. Mercury or similar material is forced through the nozzle 52, 52 by means of the pump 55, which gets its supply from the barometric seal 56, through the suction pipe 57. The nozzles 53 aresupplied by the pump 58 from the barometroic seal through the pipe 5$) and the nozzles 54, 54 are supplied by the' pump 60 from the barometric seal through the suction pipe 61. The mercury passes through the restricted area 51 with lllll considerable velocity until it reaches the section of larger area 62 where its velocity will be decreased. With its portion 62 of larger area is in effect a Venturi nozzle. It then passes under the felt roll 10 into the pipe (ii-land backto the barometric seal 56. Should the velocity of the mercury through these different nozzles 52, 58 and 54.- not be sufficient, on anyparticular adjustment of the-punips,-' to prevent some of the mercury Working back into the vacuum chamber 1, this incrcuryiscaug ht in the 'Wll 64 and passes through the pipe 65 back to the barometric seal 56. The end 66 of the pipe 65 is mounted below the level of the suction pipes 57, 59 and 61 so that it Will be impossible to break the vacuum in the vacuum chamber by speeding up the pumps 55, 58 or 60. These pumps are all run by one motor 67 through .a shaft 68 and gearing 69. Of course theymay be operated by separate motors if desired.

In Fig. 6 I have shown a further modifi- I siderable velocity as it passes through the restricted area 81, its velocity falling as it reaches the portion 82 of larger area. The suction pipe 88 of the second pump. 84: is connected with thelarger area 82 ,andgets its supply from that areafi It then pumps thefluid through the nozzles 77 and the second restricted area 85, the velocity of the fluid again decreasing asit reaches the second large' area 86. The suction pipe 87 of the third pump 88 is c onnected'with the large area 86 and "pumps the fluid through the nozzle 78, the fluid then passing through they-third large area 89 into the felt roll housing 11. The pumps may be driven in any suitable manner. driven, for example, byv the motor 90- through. the common shaft 91. The pipe 63 connects the-felt roll housing 11 Withthe barometric seal 56. While I have shown three sets of'nozzles and restricted and enlarged areas, for purpose. of illustration, it is of course to be understood that. any number desired may be used.

While I preferably use mercury as the fluid of my velocity fluid seals shown in Figs. 1 to 6 inclusive it is of course to "be understood that the liquid might be an amal- The restricted passage 51' I have shown themgain or any-other suitable material having no affinity-for the web treated and no dele-,.

terious effect upon it. It is also, of course,

to be understood that the vacuum chamber of Fig. 7 may beequipped with oneor more drying drums orcylinders such as 3, 1, 5 and 6.

Instead of arranging my velocity fluid seal horizontally asshown in Figs. 1 to 'Z inclusive, I may arrange it at any suitable angle to the horizontal, in which case therc will be more or less static head. In Fig. 8 I

haveshown my velocit fluid seal'at ri ht y y s angles to the horizontal' In this figure the felt roll housing: is

connected with a'vert-icalpassage 111 having a restricted area 112. This passage 111 opens lnto the vacuum chamber 113- Within which are mounted one or more drying drums 0r cylinders 11%.

If mercury or other similar material be used as the fluid of my seal itWill fill the felt roll housing 1-10 reaching the level 115 on the' surface exposed to the atmosphere and the level. 116 in the passage 111,. yThe height in the passage of course Will depend on the degree of vacuum in'the vacuum chamber The mercurylor similar materialforming the fluid of the velocity fluid seal passes through the restricted area 112,

e and through the pipe 117 into the barometric w seal 118. The suction pipe 1190f the' pressure pump Withdraws the fluid from the barometric seal 118 and is arranged as described in the other figures'so as not tov I break the barometric I seal.

The pressure pump 120 is driven in any suitable manner,

as by the motor 121, and forces the. fluid through the pipe 122 and into the felt roll housing 110.

The height of the column of mercuryor similar material in the'passage 111rmay be varied. Assuming, for example, that the VILCLT \.1II1 maintained in a vacuum chamber is 28 inches of mercury, and the column of mercury, in the passage is 18 inches, this column of mercury or similar materialacts as a static head and Will lessen the amount of. fluid Which Will'have to be pumped by.

the pump 121. I

\Vith the apparatus arranged as above described the 18 inches .of mercury or similar material balances 18 inches of vacuum in the'vacuumchamber 113. As the vacuum maintained therein is, for example, 28 inc-hes, therewill be a differenc of only 10 inches which will have to be overcome or compensated for by the pump 120 pumping the fluid through the restricted passage 112 and around through the barometric seal 118, suction pipe 119,-pressure' pump 120 and pipe 122. In other Words the pump 1nstead of pumpmg the fluid at a velocity suflicient to overcome a vacuum of 28 inches of mercury will, with this static head of 18 inches, only have to pump the fluid of the seal at a suflicient velocity to overcome a vacuum of 10 inches of mercury. Of course, different degrees of vacuum, and dilterent static heads may be employed without departing from my invention. It is of course to be understood that any of the other types of seals shown in other ligures of the drawings can be arranged at an angle to the horizontal, or vertically, as shown in Fig. 8. i

My method possesses many advantages not present in processes heretofore used for many years in the drying of paper.

The evaporation process, which is characteristic of the so-called'loft drying of paper, has many fully recognized disadvan- -tages, and yet it is used today and has been in use for many years. In this method the wet paper is taken from the paper machine, cut into sheets, hung on poles, carried to the drying room where it is subjected to hot air at about 130. F; for about 48 hours, and when dry, each sheet is separately calendered. Although possessing the advantage of drying at a comparatively low temperature, whereby the moistureis slowly evaporated, loft drying-is obviously very inefficient and costly, because it requires many separate manipulations,is extremely slow, uses extensive floor space and wastes heat. I

The process which is employed in the or.

dinary paper machine in. common use, is likewise subject to many disadvantages. In such machine, the wet paper as it comes from the paper machine, is passed over many revolving cylinders, heated internally by steam to sufficiently high degree of heat, to raise th temperature of the water in the paper to 212 F., the atmospheric boil- .ing point of water. It is customary to supply the drying cylinders with steam at approximately pounds gauge pressure, at which the steam has a temperature of 228 F, giving a difference of temperature (228 2l2 of only 16 F. With this slight difference of temperature the transfer of heat is extremely slow, and hence it is necessary to employ many drying cylinders, in board machines often one hundred, and in news print machines, forty or more.

Also due to convection and conduction losses, as well as those incident to leaks in per is driven ofi' into-th operating room, 7

restart;

and although .fans and exhausters are em} ployed, at large expense for power and maintenance, the room atmosphere is so constantly saturated with moisture as to rust and ultimately destroy all iron and steel materials, and produces an exceeding- 1y disagreeable and unhealthy atmosphere in which to work. It is well known that the mini-mum temperature 212, the atmosequipped with a blower system by which air, either heated or not, is blown through the dryer section, which will lower the temperature at which the water is evaporated from the paper much below 212 F. and may, in some cases, reduce the temperature of evaporation as low as 180 F. or lower.

In my improved vacuum drying method I contemplate maintaining within the chamber a vacuum of about 28 of mercury, in which water boils at .F., and

'supplying the drying cylinders with steam at 5.3 pounds gauge pressure, producing a temperature of 228 F. The temperature difference between the temperature of the steam-in the cylinders and that of the paper, is therefore, 128 F. in my vacuum method, or 8 times greater (16 8:128 F.) than the temperature difference in atmospheric drying. In my improved method-t-he paper dries approximately 8 times faster than in atmospheric drying, and I require only about one-eighth the number of drying cylinders to dry paper at'the same rate of speed; I am able to dry paper with 5 cylinders in the same time required of to cylinders drying at atmospheric pressure, resulting in great economies in cost of th machine, floor space and of necessary piping, 'felts, auxiliary equipment,

and particularly in power and maintenance charges.

The thermal efiiciency of my vacuum method is very much greater than that of the atmospheric cylinder drying heretofore in universal use for drying paper. Theoretically, it requires about 5287 pounds of steam to dry one ton ofpaper at atmospheric pressure, but to compensate for convection and conduction losses, and those due to leaks in the piping system, and other inefliciencies, it has been shown in practice that about 10,600 pounds arerequired.

in my method, using a va uum; of about Paper dried in a'vacuum of 28, or at. a temperature of about 100 'F., as farmymethod, is very much stronger than paperthe ,process is carried on in a vacuum cham-- 'away to the condenser.

28", the convection, conduction and piping losses are exceedingly small and the total steam required to dry 9. ton of paper by dried at atmospheric pressure, when the steam in the dryers is at 228 F. .W'hen paper is .dried by my method, there-fore, a

cheaper furnish or stock can be used and" still produce a paper equal in strength to atmospheric dried paper, in which a. highor grade furnish or stock-is used. In mak-.

ing newsprint paper, I am able to dispense with a considerable portion of the more expensive sulphite pulp, as this can be replaced withthe cheaper ground wood pulp. By my method I also reduce the number of breaks in the web as it passes over the cylinder. t ,v v

-Furthermore, in my method there is a great saving of heat (or-steam) because her which acts on the principleof a thermos bottle, and the steam and vapors driven out of the wet paper are caught in the closed vacuum chamber, and, conducted room is free, from steam, humidity and heat, and fans, and exhausters are dispensed with. In the use of mymethod the apparatus is at all times operating under definitehumidity, the control of the drying 'can be closely standardized, and the moisture content in the-paper carefully regulated. Having pointed out the manyadvantages of my method and apparatus over those heretofore used, it will. be apparent that. the

use of my invention results in' great economy in the initial cost of apparatus and in large savings in cost of operation, maintenance and repairs.

By the terms velocity fluid seal or velocity fluid seals as. used-in'this application, 1 mean any moving fluid seal, sealing the opening or openings of the vacuum chamber, and flowing into, or out of, the vacuum chamber, orjtendin'g to flow into or out of the vacuum chamber, and through which the material to be treated is passed in any-suitable manner.

Having thus described this invention in connection W1thdifi'erent illustrative embodiments thereof, tothe details of which I do not desire to be limited, what is claimed as new andwhati's desired to secure by Letters Patent is set -forth in the 'fber through velocity fluid seals,

said web while in the vacuum chamber.

ended claims.

P at I claim is 2-- The operating 1.. The method of sealing a vacuum chamber having an openmg for the admission of material into said vacuum chamher to be treated consisting in preventing admission of air through said opening by sealing said opening with a fluid through which the material to be treated passes into i the vacuum chamber, and causing said fluid to flow.

i 2. The method of sealing a vacuum chamber havingopenings for the admission of material to be treated into and out of sald vacuum chamber, .consisting in preventing the'admission of air through said openings by sealing said openings with a fluid through which the material passes into and out of the vacuum chamber, and causing said fluid to flow.

3. The method of continuously passing sheet material into and out of a vacuum chamber consisting in continuously feeding it into and out of a vacuum chamber through a fluid which prevents air gettinginto the vacuum chamber, andcausing said fluid to flow. p

4. The method of continuously passing sheet material into and out of a vacuum chamber consisting in continuously feeding it into and out of a vacuum chamber through liquid seals, causing said liquid to move in the direction of travel of the sheet material thereby preventing air getting into the vacuum chamber.

5. Inla vacuum apparatus the-combination-of a vacuum chamber provided with one or more openings for the admission and withdrawal of material to be treated into and fromsaid vacuum'chamber, and one or more velocity fluidseals protecting said opening or openings and preventing the ad mission of air into said vacuum chamber.

6. In a vacuum apparatus the combination of a vacuum chamber provided with one or more openings for the admission and withdrawal of material to be treated into and from said vacuum chamber, and one or more velocity fluid seals protecting said opening or openings and preventing the admission of air into said vacuum chamber and-means to collect the fluid of the seal.

7. In a vacuum apparatus the combination ofla vacuum chamber provided with one or more openings for the admission and withdrawal of material to be treated into and from said vacuum chamber, and one or more velocity fluid seals protecting said opening or openings and preventing the admission of air into said vacuum chamber and again deliver the same to the velocity fluid seal.

8. The method of continuously drying a til permitting 9. The method of continuously drying a web of wet paper consisting in continuously feeding the web into and out of a vacuum chamber through mercury, amalgam or similar material causing said mercury or similar material to move, and drying said web in said'vacuum chamber.

it). The method of sealing a vacuum chamber having an opening for the admission of material into said vacuum chamber to be treated consisting in preventing the admission of air through said opening by a sealing medium to flow through said opening into the vacuum chamber and removing said sealing medium from said vacuum chamber,

11. The method of sealing a vacuum chamber havin an opening for the admission of material into said vacuum chamber to be treated consisting in preventing the admission o'lf air throughsaid opening by" permitting a sealing medium to flow through said opening into the vacuum chamber and removing said sealing mediunrfrom said vacuum chamber and again using the removed scaling medium by permitting it to low through said opening.

12. In a vacuum apparatus the combination of a vacuum chamber having one or more restricted passages through which the material to be treated is passed, means to supply a sealing liquid'through said restricted passage or passages, said sealing liquid sealing the vacuum chamber and pass ing into the vacuum chamber with the material to be treated, and means to withdraw --said sealingfiuid from the vacuum chamliquid sealing the vacuum chamber and passing into the vacuum chamber'with the "material to be treated, and means to withdraw said sealing-liquid from the vacuum chamber, and again deliver the same to said one or more restricted passages to be again used.

14. In a vacuum apparatus the combination of a vacuum-chamber provided with one ormore openings for the admission and withdrawal of material into and from said vacuum chamber to be treated, and one or more liquid seals flowing into the vacuum chamber through said opening or openings and preventing the admission of air into the vacuum chamber and means to withdrawsaid liquid from the vacuum chamber.

15. In a vacuum apparatus the combination of a vacuum chamber provided with one or more openings for the admission and withdrawal of material into and from said vacuum chamber to be treated, and one or more liquid seals flowing into the vacuum chamber through said opening or openings and preventing the admission of air into the vacuum chamber and one or more barometric seals to withdraw saidliquid from the vacuum chamber.

16. The method of sealing the entrance and exit openings of a vacuum chamber through which a wet web of paper is fed, said method consisting in feeding the web of wet paper and a liquid into and out of the vacuum chamber, the liquid sealing the.

openings.

17. The method of sealing'the entrance and exit openings of a vacuum chamber through which a wet web of paper is fed, said method consisting in feeding the web of wet paper and a liquid into the vacuum chamber, the liquid sealing the openings, and withdrawing the fluid from the vacuum chamber.

18. The method of sealing the entrance and exit openings of a vacuum chamber through which a wet web of paper is fed, said method consisting in feeding the web of wet paper and mercury, amalgam or similar material into the vacuum chamber, the mercury, amalgam or similar material sealing the openings.

- OGDEN MINTON. 

